Bicycling

Bicycling is a fascinating sport in which small advantages between riders make the entire difference. Fine adjustments of the bicycles or exercise strategies can mean the difference between victory and defeat. With the complexity of the mechanics of the human body, the road to improved performance remains any man's guess.

On the other hand, bicycling is one of the cases that are very well-suited for analysis by the AnyBody Modeling System. It is a highly repetitive task, and it is a good assumption that the rider is capable of recruiting muscles optimally for the task. Furthermore, AnyBody bicycle models have shown good agreement with experimental results in terms of muscle recruitment as well and predicted pedal forces. So with the type of rigorous mechanical model provided by the AnyBody Modeling System, quantitative answers can be provided about the consequence of design changes.

For bicycle modeling for a particular rider it is advisable to combine the investigations with experimental activities to make sure that the correspondence between the model and the the rider is maintained when the parameters of the model are changed. The model can then be used to predict the parameter changes that can improve performance. Click here for an animation.

Strength training and rehabilitation

Most strength-based sports performances are not only about strength. They are about the right strength. Ths is because muscles are heavy, and there is no need to add muscle mass that does not add to the performance. The AnyBody Modeling System can help identify the muscles that are currently the bottleneck for performance improvment, and it can subsequently design exercises for improvement of precisely these muscles.

After an injury to a joint or a ligament, it is often desirable to strengthen the muscles surrounding the joint in question to stabilize the joint. But how can this be done without causing undue loads on the injured elements? Let us consider a simple load on the foot and examine how the position of this load influences the shear forces in the knee. Click here to see a video animation of the moving force and the corresponding muscle loads in the leg.

If we subsequently investigate the computed knee shear forces, which are carried by the cruciate ligament, then it turns out that the force location under the foot plays a very important role, and indeed there is one particular position of the foot force that completely eliminates the knee shear force.

Knee shear force for different force positions under the foot.

Fitness equipment is a major field of application of the AnyBody Modeling System. The system's ability to model the mechanism of the machine and its interaction with the human body creates the opportunity of optimizing the machine's load of the muscular system. 

Fitness machine. Click to see the video (6.4 MB)

The objective of this example is to adjust the eccentricity of the cable wheel such that the arm muscles experience a constant effort throughout the elbow flexion taking the change of moment arms of the muscles into account. The graph below shows the difference between a cable wheel with no eccentricity and one that has been adjusted based on the AnyBody simulation.

It is not possible to obtain a completely constant muscle effort with only the eccentricity as parameter. However, if more parameters were introduced into an actual design optimization, then it is likely that an almost completely uniform effort profile could be obtained.

It is also possible to invesigate the effect of free lifting of weights ans in the bench press example below. Typical uses of the model in this situation is to investigate the effect of hand positions or elbow postures on muscle exercise.

Click to view video (2 MB)

Baseball swing

This is actually not a real baseball swing. In the absence of correct movement data the model is driven by made-up joint angle variations and trajectories for the bat. The blue and red dots in the model represent interpolation points for the bat trajectories. It would not be difficult to impose the true movement from a motion capture experiment.

Click here to see the animation.

Swimming

Until recently, there have been no studies of the musculoskeletal analysis for swimming because of the difficulty to estimate the fluid force acting on the swimmer's whole body, although such analysis could prove to be valuable information for the athlete swimmer's training and coaching.

Now, a full-body musculoskeletal simulator for swimming has been developed for the AnyBody Modeling System, which enables to calculate fluid force acting on the whole body during swimming. The model presents 4 swimming styles: Crawl, Breststroke, Backstroke, and Butterfly.

The research on swimming has been conducted by a research group at Tokyo Institute of Technology, led by Dr. Nakashima. You can visit the research homepage here: http://www.swum.org/index.html.

See Dr. Nakashima’s previously held webcast on Development of a Musculoskeletal Simulator for Swimming…